JavaScript代码片段

简介：本文收集了我常用的JavaScript代码片段，欢迎提意见！

大灰狼边敲门边说：“小兔子乖乖，把门儿开开！”
小兔子听到后，连忙去开门：“来喽！”
兔妈妈对小兔子喊道：“不许开！是大灰狼！”
大灰狼在门口感叹道：“哎，骗一个女孩容易，骗一个女人难呀！”

JavaScript动态加载

//NO.1
function loadScript(url, callback){
    var script = document.createElement ("script")
    script.type = "text/javascript";
    if (script.readyState){ //IE
        script.onreadystatechange = function(){
            if (this.readyState == "loaded" || this.readyState == "complete"){
                this.onreadystatechange = null;
                callback();
            }
        };
    } else { //Others
        script.onload = function(){
            callback();
        };
    }
    script.src = url;
    document.getElementsByTagName("head")[0].appendChild(script);
}

//NO.2
function loadScript(url, callback){
    var xhr = new XMLHttpRequest();
    xhr.open("get", url, true);
    xhr.onreadystatechange = function(){
        if (xhr.readyState == 4){
            if (xhr.status >= 200 && xhr.status < 300 || xhr.status == 304){
                var script = document.createElement ("script");
                script.type = "text/javascript";
                script.text = xhr.responseText;
                document.body.appendChild(script);
                callback();
            }
        }
    };
    xhr.send(null);
}

DOM加载完执行

function domLoad(fn){
    if(document.addEventListener){
        document.addEventListener("DOMContentLoaded", fn, false);
    }else{
        if(window.ActiveXObject){
            document.write("<script id='ie_onload' defer src='javascript:void(0)'></script>");
            document.getElementById("ie_onload").onreadystatechange = function(){
                if(this.readyState == "complete"){
                    this.onreadystatechange = null;
                    fn();
                }
            }
        }
        if(/WebKit/i.test(navigator.userAgent)){
            var _timer = setInterval(function(){
                if(/loaded|complete/.test(document.readyState)){
                    clearInterval(_timer);
                    fn();
                }
            }, 10);
        }
    }
}

是否标准模式(IE)

function isCompatMode(){return document.compatMode == 'CSS1Compat';}

Link规则操作

//添加第一条规则
//insertRule(sheet, 'body', 'background-color:red', 0);
function insertRule(sheet, selectorText, cssText, position) {
    if (sheet.insertRule) {
        sheet.insertRule(selectorText + ' { ' + cssText + ' }', position);
    } else if (sheet.addRule) {
        sheet.addRule(selectorText, cssText, position);
    }
}


//删除第一条规则
//deleteRule(sheet, 0);
function deleteRule(sheet, position) {
    if (sheet.deleteRule) {
        sheet.deleteRule(position);
    } else if (sheet.removeRule) {
        sheet.removeRule(position);
    }
}

加载样式表

function addSheet(url){
    var oLink = document.createElement('link'),oHead = document.getElementsByTagName('head')[0];
    oLink.rel = 'stylesheet';
    oLink.type = 'text/css';
    oLink.href = url;
    oHead.appendChild(oLink);
}

获取CSS样式

function getStyle(o, attr){
    if(o.currentStyle){
        return o.currentStyle[attr];
    }
    else{
        return getComputedStyle(o,false)[attr];
    }
}

getByClass

function getElementsByClassName(classname, parent, nodename) {
    var parent = parent || document, nodename = nodename || "*";
    if(parent.getElementsByClassName){
        return parent.getElementsByClassName(classname);
    }else{
        var l = parent.getElementsByTagName(nodename);
        return function () {
            var res = [];
            for (var i = 0, j = l.length; i < j; i++) {
                if (l[i].className){
                    var name = " " + l[i].className + " ";
                    if (name.indexOf(" " + classname + " ") != -1) {
                        res.push(l[i]);
                    }
                }
            }
            return res;
        } ();
    }
}

hasClass

function hasClass (element, className){
    return element.className.match(new RegExp('(\s|^)'+ className +'(\s|$)'));
}

addClass

function addClass(element, cName) {
    if (!hasClass(element, cName)) {
        element.className += ' ' + cName;
    }
}

removeClass

function removeClass(element, cName) {
    if (hasClass(element, cName)) {
        element.className = element.className.replace(new RegExp('(\s|^)' + cName + '(\s|$)'), ' ');
    }
}

JSONP调用

<script src="http://www.xxx.com?name=fnCall"></script>
<script>
function fnCall(info){
    // 在前台提供一个方法fnCall的方法
    // http://www.xxx.com?name=fnCall 在(后台/其他页面)自动获取fnCall的名字并且执行
}
</script>

获取服务器时间

function getNowDate(callback){
    var xhr = new XMLHttpRequest();
    xhr.open('get', 'null.txt', true); //null.txt不存在，我们不需要
    xhr.onreadystatechange = function(){
        if(xhr.readyState == 3){ //状态3响应
            callback(xhr.getResponseHeader('Date')); //返回时间，那么可以利用获得的时间做倒计时程序了。
        }
    };
    xhr.send(null);
}

Cookie操作

function Cookie(name, value, options){
    if(typeof value != 'undefined'){
        options = options || {};
        if(value === null){
            options.expires = -1; //过期
        }
        var expires = '';
        //存在时间选项
        if(options.expires && (typeof options.expires == 'number' || options.expires.toUTCString)){
            var date;
            if(typeof options.expires == 'number'){
                date = new Date();
                date.setTime(date.getTime() + (options.expires * 24 * 60 * 60 * 1000));
            }else{
                date = options.expires;
            }
            expires = '; expires='+date.toUTCString();
        }
        var path = options.path ? '; path='+options.path : '';
        var domain = options.domain ? '; domain='+options.domain : '';
        var secure = options.secure ? '; secure' : '';
        //写入cookie
        document.cookie = [name, '=', encodeURIComponent(value), expires, path, domain, secure].join('');
    }else{//读取cookie
        var cookValue = null;
        if(document.cookie && document.cookie != ''){
            var cookie = document.cookie.split(';');
            for(var i = 0, len = cookie.length; i < len; i++){
                var c = cookie[i].replace(/^s+|s+$/g, '');
                if(c.substring(0, name.length + 1) == (name + '=')){
                    cookValue = decodeURIComponent(c.substring(name.length + 1));
                    break;
                }
            }
        }
        return cookValue;
    }
}
//设置
Cookie("user", "Jununx");
//获取
Cookie("user");
//删除
Cookie("user", null);

base64编码解码 

function b64Encode(str) {
  return btoa(unescape(encodeURIComponent(str)));
}

function b64Decode(str) {
  return decodeURIComponent(escape(atob(str)));
}

浏览器判断

var browser = function() {
    var u = navigator.userAgent.toLowerCase();

    return { 
        version: (u.match(/.+(?:rv|it|ra|ie|chrome|micromessenger|version)[/: ]([d.]+)/) || [])[1],     
        safari: /safari/.test(u) && !/chrome/.test(u), 
        opera: /opera/.test(u), 
        msie: /msie|like gecko$/.test(u) && !/opera/.test(u), 
        firefox: /firefox/.test(u) && !/(compatible|webkit)/.test(u),
        chrome: /chrome/.test(u) && /safari/.test(u),  
        
        mobile: !!/applewebkit.*mobile.*/.test(u),
        ios: !!/(i[^;]+;( u;)? cpu.+mac os x/.test(u),
        android: /android|linux/.test(u), // android或uc
        iPhone: /iphone/.test(u),
        iPad: /ipad/.test(u),
        weChat: /micromessenger/.test(u) // 微信
    };
};

IE版本判断

var _IE = (function(){
    var v = 3, div = document.createElement('div'), all = div.getElementsByTagName('i');
    while (
            div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i><![endif]-->',
                    all[0]
            );
    return v > 4 ? v : false ;
}());

阶乘缓存

function memfactorial(n){
    if(!memfactorial.cache){
        memfactorial.cache = {
            "0" : 1,
            "1" : 1
        };
    }
    if(!memfactorial.cache.hasOwnProperty(n)){
        memfactorial.cache[n] = n * memfactorial(n - 1);
    }
    return memfactorial.cache[n];
}

获取字符串长度

// NO.1
String.prototype.sLen = function(){
    var b = 0, l = this.length;
    if(l){
        for(var i = 0; i < l; i++){
            if(this.charCodeAt(i) > 255){
                b += 2;
            }else{
                b ++;
            }
        }
        return b;
    }else{
        return 0;
    }
};

// NO.2
String.prototype.sLen = function(){
    var b = 0, l = this.length;
    if(l){
        for(var i = 0; i < l; i++){
            var c = this.charAt(i);
            if(escape(c).length > 4){
                b += 2;
            }else if(c != '
'){
                b ++;
            }
        }
        return b;
    }else{
        return 0;
    }
};

// NO.3
String.prototype.sLen = function(){
    var b = 0, l = this.length;
    if(l){
        for(var i = 0; i < l; i++){
            var c = this.charAt(i);
            if(/^[u0000-u00ff]$]/.test(c)){
                b ++;
            }else if(c != '
'){
                b += 2;
            }
        }
        return b;
    }else{
        return 0;
    }
};

// NO.4
String.prototype.sLen = function(){
   var s = this.replace(/[^x00-xff]/g, "**");
   return s.length;
};

判断数据类型

var isType = function(obj, type){
    return Object.prototype.toString.call(obj) === '[object '+ type +']';
};

获取窗口位置

function sereen(){
    return {
        left : window.screenLeft || window.scrollX,
        top : window.screenTop || window.scrollY
    };
}

获取可视窗口大小

function client(){
    //IE6不加dtd会进入怪癖模式，client需要通过document.body获取
    return {
        width : document.documentElement.clientWidth || document.body.clientWidth,
        height : document.documentElement.clientHeight || document.body.clientHeight
    };
}

获取scrollTop

function getScrollTop(){
    if(typeof pageYOffset!= 'undefined'){
        return pageYOffset;
    } else {
        return (document.body || document.documentElement).scrollTop;
    }
}

滚动到指定区域

el.scrollIntoView()

今天星期几

"今天是星期" + "天一二三四五六".charAt(new Date().getDay())

页面是否在iframe里

if(self==top){
    //not in iframe
}else{
    //in iframe
}

返回最小值~最大值之间随机数

function random(min, max) {
    return Math.floor(Math.random() * (max - min + 1) + min);
}

数组去重

// NO.1
Array.prototype.unique = function() {
    for(var i=0, len = this.length; i<len; i++) {
        for(var j=i+1; j<len; j++) {
            if(this[i] === this[j])
                this.splice(j, 1);
        }
    }
    return this;
};
// ["a","a","b"].unique();

// NO.2
Array.prototype.unique = function (){
    var that = this, temp = {}, result = [];
    for(var i = 0, len = that.length; i < len; i++) {
        if(!temp[typeof (that[i])+that[i]]){
            result.push(that[i]);
            temp[typeof(that[i])+that[i]] = '1';
        }
    }
    return result;
}
// ["a","a","b"].unique();

数组快排

function quickSort(arr) {
    if (arr.length < 2) {
        return arr;
    }
    var pivotIndex = Math.floor(arr.length / 2);
    var pivot = arr.splice(pivotIndex, 1)[0];
    var left = [];
    var right = [];
    for (var i = 0, j = arr.length; i < j; i++) {
        if (arr[i] < pivot) {
            left.push(arr[i]);
        } else {
            right.push(arr[i]);
        }
    }
    return quickSort(left).concat([pivot], quickSort(right));
}
var test = quickSort([1,9,2,8,3,7,4,6,5]);

将arguments转换成数组

var arr = Array.prototype.slice.call(arguments, 0);

数组随机排序

var arr = [1, 2, 3, 4, 5];
arr.sort(function(){
    return (Math.random() - 0.5);
});

获取数组中最小/大值

var max = Math.max.apply(null, array);
var min = Math.min.apply(null, array);

数组index

function index(t, arr){
    if(arr.indexOf){
        return arr.indexOf(t);
    }
    for(var i = arr.length ; i--; ){
        if(arr[i]===t){
            return i*1;
        }
    }
    return -1;
}

多维数组转一维数组

function arr2ToArr(arr){
    return arr.toString().split(",");
}

选择数组中两数之和等于某值的情况 

// NO.1
var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], result = [], count = 10;
for(var i = 0, len = arr.length; i < len; i ++){
    for(var j = i + 1; j < len; j ++){
        if(arr[i] + arr[j] === count){
            result.push([arr[i], arr[j]]);
        }
    }
}

// NO.2
var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], result = [], count = 10;
for(var i = 0, len = Math.round(arr.length/2); i < len; i ++){
    if(arr.indexOf(count - arr[i]) !== -1){
        result.push([arr[i], count - arr[i]]);
    }
}

数字金额转换成大写

function digit_uppercase(n) {
    var fraction = ['角', '分'];
    var digit = [
        '零', '壹', '贰', '叁', '肆',
        '伍', '陆', '柒', '捌', '玖'
    ];
    var unit = [
        ['元', '万', '亿'],
        ['', '拾', '佰', '仟']
    ];
    var head = n < 0? '欠': '';
    n = Math.abs(n);

    var s = '';

    for (var i = 0; i < fraction.length; i++) {
        s += (digit[Math.floor(n * 10 * Math.pow(10, i)) % 10] + fraction[i]).replace(/零./, '');
    }
    s = s || '整';
    n = Math.floor(n);

    for (var i = 0; i < unit[0].length && n > 0; i++) {
        var p = '';
        for (var j = 0; j < unit[1].length && n > 0; j++) {
            p = digit[n % 10] + unit[1][j] + p;
            n = Math.floor(n / 10);
        }
        s = p.replace(/(零.)*零$/, '')
                .replace(/^$/, '零')
                + unit[0][i] + s;
    }
    return head + s.replace(/(零.)*零元/, '元')
            .replace(/(零.)+/g, '零')
            .replace(/^整$/, '零元整');
}

日期格式化

Date.prototype.toString=function(format,loc){
    var time={};
    time.Year=this.getFullYear();
    time.TYear=(""+time.Year).substr(2);
    time.Month=this.getMonth()+1;
    time.TMonth=time.Month<10?"0"+time.Month:time.Month;
    time.Day=this.getDate();
    time.TDay=time.Day<10?"0"+time.Day:time.Day;
    time.Hour=this.getHours();
    time.THour=time.Hour<10?"0"+time.Hour:time.Hour;
    time.hour=time.Hour<13?time.Hour:time.Hour-12;
    time.Thour=time.hour<10?"0"+time.hour:time.hour;
    time.Minute=this.getMinutes();
    time.TMinute=time.Minute<10?"0"+time.Minute:time.Minute;
    time.Second=this.getSeconds();
    time.TSecond=time.Second<10?"0"+time.Second:time.Second;
    time.Millisecond=this.getMilliseconds();
    time.Week=this.getDay();

    var MMMArrEn=["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"];
    var MMMArr=["一月","二月","三月","四月","五月","六月","七月","八月","九月","十月","十一月","十二月"];
    var WeekArrEn=["Sun","Mon","Tue","Web","Thu","Fri","Sat"];
    var WeekArr=["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];

    var oNumber=time.Millisecond/1000;

    if(format!=undefined && format.replace(/s/g,"").length>0){
        if(loc!=undefined && loc =="en"){
            MMMArr=MMMArrEn.slice(0);
            WeekArr=WeekArrEn.slice(0);
        }
        format=format
                .replace(/yyyy/ig,time.Year)
                .replace(/yyy/ig,time.Year)
                .replace(/yy/ig,time.TYear)
                .replace(/y/ig,time.TYear)
                .replace(/MMM/g,MMMArr[time.Month-1])
                .replace(/MM/g,time.TMonth)
                .replace(/M/g,time.Month)
                .replace(/dd/ig,time.TDay)
                .replace(/d/ig,time.Day)
                .replace(/HH/g,time.THour)
                .replace(/H/g,time.Hour)
                .replace(/hh/g,time.Thour)
                .replace(/h/g,time.hour)
                .replace(/mm/g,time.TMinute)
                .replace(/m/g,time.Minute)
                .replace(/ss/ig,time.TSecond)
                .replace(/s/ig,time.Second)
                .replace(/fff/ig,time.Millisecond)
                .replace(/ff/ig,oNumber.toFixed(2)*100)
                .replace(/f/ig,oNumber.toFixed(1)*10)
                .replace(/EEE/g,WeekArr[time.Week]);
    }
    else{
        format=time.Year+"-"+time.Month+"-"+time.Day+" "+time.Hour+":"+time.Minute+":"+time.Second;
    }
    return format;
}

var d=new Date();
console.log(d.toString());    //2012-7-27 9:26:52
console.log(d.toString(""));    //2012-7-27 9:26:52
console.log(d.toString("yyyy-MM-dd HH:mm:ss"));    //2012-07-27 09:26:52
console.log(d.toString("yyyy年MM月dd日 HH:mm:ss"));    //2012年07月27日 09:26:52
console.log(d.toString("yyyy-MM-dd HH:mm:ss fff"));    //2012-07-27 09:26:52 237
console.log(d.toString("yyyy年 MMM dd EEE"));    //2012年 七月 27 星期五
console.log(d.toString("yyyy MMM dd EEE","en"));    //2012 Jul 27 Fri

五种继承方式

//构造函数的继承的五种方式
function Animal() {
    this.species = "dong wu";
}

// NO.1 构造函数绑定
function Cat(name, color) {
    Animal.apply(this, arguments);
    this.name = name;
    this.color = color;
}

// NO.2 prototype模式
function Cat (name, color) {
    this.name = name;
    this.color = color;
}
Cat.prototype = new Animal();
Cat.prototype.constructor = Cat;

// NO.3 直接继承prototype
function Cat(name, color) {
    this.name = name;
    this.color = color;
}
Cat.prototype = Animal.prototype;
Cat.prototype.constructor = Cat;

// NO.4 利用空对象做中介
function Cat(name, color) {
    this.name = name;
    this.color = color;
}

function F(){}
F.prototype = Animal.prototype;

Cat.prototype = new F();
Cat.prototype.constructor = Cat;


// NO.5 拷贝继承
function Cat(name, color) {
    this.name = name;
    this.color = color;
}

function extend(Child, Parent) {
    var p = Parent.prototype;
    var c = Child.prototype;
    for (var i in p) {
        c[i] = p[i];
    }
    c.uber = p;
}
extend(Cat, Animal);

根据生日算年龄

function getAge(dateString) {
    var today = new Date();
    var birthDate = new Date(dateString);
    var age = today.getFullYear() - birthDate.getFullYear();
    var m = today.getMonth() - birthDate.getMonth();
    if (m < 0 || (m === 0 && today.getDate() < birthDate.getDate())) {
        age--;
    }
    return age;
}
console.log(getAge("1990,1,12"));

事件绑定

var events = (function(win){

    // 事件绑定
    function on(el, ev, fn){
        if(el.addEventlistener){
            on = function (el, ev, fn) {
                el.addEventlistener(ev, fn, false);
            };
        } else if(el.attachEvent){
            on = function(el, ev, fn){
                el.attachEvent('on' + ev, function(){
                    fn.call(el); // IE This
                });
            };
        } else {
            on = function(el, ev, fn){
                el['on' + ev] = fn;
            };
        }
        on(el, ev, fn);
    }

    // 解除事件绑定
    function off(el, ev, fn){
        if(el.removeEventlistener){
            off = function (el, ev, fn) {
                el.removeEventlistener(ev, fn, false);
            };
        } else if(el.detachEvent){
            off = function(el, ev, fn){
                el.detachEvent('on' + ev, fn);
            };
        } else {
            off = function(el, ev){
                el['on' + ev] = null;
            };
        }
        off(el, ev, fn);
    }

    // 获取事件对象
    function getEvent(ev){
        return ev || win.event;
    }

    // 获取事件目标
    function getTarget(ev){
        return ev.target || ev.srcElement;
    }

    // 获取键值
    function getKeyCode(ev){
        if (typeof ev.charCode == 'number'){
            getKeyCode = function(ev){
                return ev.charCode;
            };
        } else {
            getKeyCode = function(ev){
                return ev.keyCode;
            };
        }
        getKeyCode(ev);
    }

    // 阻止默认行为
    function preventDefault(ev){
        if(ev.preventDefault){
            preventDefault = function(ev){
                ev.preventDefault();
            };
        } else {
            preventDefault = function(ev){
                ev.returnValue = false;
            };
        }
        preventDefault(ev);
    }

    // 阻止冒泡
    function stopPropagation(ev){
        if(ev.stopPropagation){
            stopPropagation = function(ev){
                ev.stopPropagation();
            };
        } else {
            stopPropagation = function(ev){
                ev.cancelBubble = true;
            };
        }
        stopPropagation(ev);
    }

    return {
        on: on,
        off: off,
        getEvent: getEvent,
        getTarget: getTarget,
        getKeyCode: getKeyCode,
        preventDefault: preventDefault,
        stopPropagation: stopPropagation
    };
}(window));

自定义事件

var EventHandlers = {
    events: {},
    fire: function(ev, arg){
        if(this.events[ev]){
            var e = this.events[ev];
            for(var i = 0, len = e.length; i < len; i++){
                e[i](arg);
            }
        }
    },
    on: function(ev, fn){
        if(!this.events[ev]){
            this.events[ev] = [];
        }
        this.events[ev].push(fn);
    },
    off: function(ev, fn){
        if(this.events[ev]){
            var e = this.events[ev];
            for(var i = 0, len = e.length; i < len; i++){
                if(e[i] == fn){
                    e.splice(i, 1);
                    break;
                }
            }
        }
    }
};

加载获取图片尺寸

var img = new Image();
img.onload = function() {
    console.log(this.width + 'x' + this.height);
}

Object.create

var create = Object.create || function(o){
    var F = function(o){};
    F.prototype = o;
    return new F;
};

Object.prototype.bind

var bind = Object.prototype.bind || function (scope) {
    var fn = this;
    return function () {
        return fn.apply(scope);
    };
};

设置选定文本

//选定文本
function setSelectText(text, start, num) {
    if (text.setSelectionRange) {
        text.setSelectionRange(start,num);
        text.focus();
    } else if (text.createTextRange) {
        var range = text.createTextRange();
        range.collapse(true);
        range.moveStart('character',start);
        range.moveEnd('character',num - start);                //用最后的位置 - 开始的位置 = 个数
        range.select();
    }
}

获取选择文本

function getSelectedText(id){
    var o = document.getElementById(id);
    if(window.getSelection) {
        if(o.selectionStart != undefined && o.selectionEnd != undefined){
            return o.value.substring(o.selectionStart, o.selectionEnd);
        }
    }
    else{
        return document.selection.createRange().text;
    }
}

在光标位置插入字符串

// 光标位置插入字符串
function insertHtmlAtCursor(id, text){
    var o = document.getElementById(id);

    if (document.selection){
        o.focus();
        document.selection.createRange().text = text;
        o.focus();
    }
    else if (o.selectionStart) {
        var start = o.selectionStart, end = o.selectionEnd;
        o.value = o.value.substring(0, start) + text + o.value.substring(end, o.value.length);
    }
}

在url中查找指定参数的值

function getQuery(){
    var s = (location.search.length > 0 ? location.search.substring(1) : ''),
        res = {},
        items = s.length ? s.split('&') : [],
        item = null, name = null, value = null,
        i, len = items.length;

        for (i = 0; i < len; i++){
            item = items[i].split('=');
            name = decodeURIComponent(item[0]);
            value = decodeURIComponent(item[1]);
            if(name.length){
                res[name] = value;
            }
        }

    return res;
}

IE6里a:hover图片缓存

document.execCommand("BackgroundImageCache",false,true);

反转文本顺序

String.prototype.reverse = function (){
    if(this.length < 2){
        return this;
    }

    var str = this.split(''), result = '', len = this.length - 1;

    while(len >= 0){
        result += this[len];
        len --;
    }

    return result;
}

'反转文本顺序'.reverse();

清除空格

String.prototype.trim = String.trim || function() {
    return this.replace(/^s*(.*?)s+$/, "$1")
};

加入收藏

function addFavorite(url, title) {
    try {
        window.external.addFavorite(url, title);
    } catch(e) {
        try {
            window.sidebar.addPanel(title, url, "");
        } catch(e) {
            alert("加入收藏失败，请使用Ctrl+D进行添加");
        }
    }
}

设为首页

function setHomepage(url) {
    if (document.all) {
        document.body.style.behavior = 'url(#default#homepage)';
        document.body.setHomePage(url)
    } else if (window.sidebar) {
        if (window.netscape) {
            try {
                netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect")
            } catch(e) {
                alert("该操作被浏览器拒绝，如果想启用该功能，请在地址栏内输入 about:config,然后将项 signed.applets.codebase_principal_support 值该为true")
            }
        }
        var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);
        prefs.setCharPref('browser.startup.homepage', url)
    }
}

insertAfter

function insertAfter(newChild,refChild){
    var parElem=refChild.parentNode;
    if(parElem.lastChild==refChild){
        refChild.appendChild(newChild);
    }else{
        parElem.insertBefore(newChild,refChild.nextSibling);
    }
}

innerText操作

//获取innertext
function getInnerText(element) {
    if (typeof element.textContent == 'string') {
        return element.textContent;
    } else {
        return element.innerText;
    }
}
//设置innertext
function setInnerText(element, text) {
    if (typeof element.textContent == 'string') {
        element.textContent = text;
    } else {
        element.innerText = text;
    }
}

获取offsetTop

//获取offsetTop
function offsetTop(element) {
    var top = element.offsetTop;        //第一层的距离
    var parent = element.offsetParent;

    while (parent !== null) {
        top += parent.offsetTop;
        parent = parent.offsetParent;
    }
    return top;
}

构建字符串的最优方法

var arr = ['item 1', 'item 2', 'item 3', ...];  
var list = '<ul><li>' + arr.join('</li><li>') + '</li></ul>';

获取字符串中出现次数最多的字符 

// NO.1
String.prototype.strCount = function (){
    var num = 0, val = '', result = null, temp = '', that = this;
    while (that) {
        temp = that;
        val = that.substr(0, 1);
        that = that.replace(new RegExp(val, "g"), "");
        if (temp.length - that.length > num) {
            num = temp.length - that.length;
            result = {val:val, num: num};
        }
    }
    return result;
};

// NO.2
String.prototype.strCount = function (){
    var obj = {}, num = 0, val = '';
    for(var i = 0, len = this.length; i < len; i+=1){
        if(!obj[this[i]]){
            obj[this[i]] = [];
        }
        obj[this[i]].push(this[i]);
    }
    for(var arr in obj){
        if(num < obj[arr].length){
            num = obj[arr].length;
            val = obj[arr][0];
        }
    }
    return {val:val, num: num};
};

// NO.3
function strCount(str){
    var o = {}, ret = {name: '', num: 0};

    for(var i = 0, len = str.length; i < len; i++){
        if( o[str[i]] ) {
            o[str[i]]++;
        }else{
            o[str[i]] = 1;
        }

        if(ret.num < o[str[i]]){
            ret.name = str[i];
            ret.num = o[str[i]];
        }
    }

    return ret;

}

// NO.4
function strCount(str){
    var ret = {name: '', num: 0};
    str.split('').sort().join('').replace(/(w)1+/g, function($0, $1){
        if ( ret.num < $0.length ) {
            ret.num = $0.length;
            ret.name = $1;
        }
    });

    return ret;
}

对象深度clone 

var cloneObj = function(obj){
    var newobj, s;
    if(typeof obj !== 'object'){
        return;
    }
    newobj = obj.constructor === Object ? {} : [];
    if(window.JSON){
        s = JSON.stringify(obj), //系列化对象
        newobj = JSON.parse(s); //反系列化（还原）
    }else{
        if(newobj.constructor === Array){
            newobj.concat(obj);
        }else{
            for(var i in obj){
                newobj[i] = obj[i];
            }
        }
    }
    return newobj;
};

千分位表示

// NO.1
function millesimal(v){
    var num = v.length%3, prev = '', next = v.substring(num), arr = [];
    if(num !== 0){
        prev = v.substring(0, num);
        arr.push(prev);
    }
    for(var i = 0, len = next.length; i < len; i += 3){
        arr.push(next.substr(i,3))
    }

    return arr.join();
}

// NO.2
function millesimal(v){
    return v.toString().replace(/(?=(?!)(d{3})+$)/g, ',');
}

// NO.3
function millesimal(v){
    return v.toString().replace(/B(?=(d{3})+$)/g, ',');
}

替换全部

String.prototype.replaceAll = function(s1, s2) {
    return this.replace(new RegExp(s1, "gm"), s2)
}

HTML转义

// 转义html标签
function HtmlEncode(text) {
    return text.replace(/&/g, '&amp').replace(/"/g, '&quot;').replace(/</g, '&lt;').replace(/>/g, '&gt;')
}
// 还原html标签
function HtmlDecode(text) {
    return text.replace(/&amp;/g, '&').replace(/&quot;/g, '"').replace(/&lt;/g, '<').replace(/&gt;/g, '>')
}

随机字符串（字母&数字）

function randomStringNum(len) {
    var ret = "";
    for( ; ret.length < len; ret += Math.random().toString(36).substr(2));
    return ret.substr(0, len);
}

随机颜色 

// (0xffffff+1) 表示颜色最大值(0x000000 ~ 0xffffff+1)
// <<0             表示左移一位，将颜色16进制的颜色值转成整型
// toString(16) 表示再将整型的颜色值转成16进制
// slice(-6)     表示生成的16进制值少于6位时，首尾依次补0
var getRandomColor = function(){
    return '#'+('00000'+(Math.random()*(0xffffff+1)<<0).toString(16)).slice(-6);
};

curry

function currying(fn) {
    var args = [].slice.call(arguments, 1);
    return function() {
        var newArgs = args.concat([].slice.call(arguments));
        return fn.apply(null, newArgs);
    }
}

// use
var test = currying(function() {
    console.log(arguments);
}, 'a');

test(1);

uncurrying

Function.prototype.uncurrying = function(){
    var self = this;
    return function(){
        return Function.prototype.call.apply(self, arguments);
    }
};

函数节流

// 函数节流
var throttle = function(fn, interval){
    var self = fn,
        timer,
        firstTime = true;

    return function(){
        var args = arguments,
            that = this;

        if(firstTime){
            self.apply(that, args);
            return firstTime = false;
        }

        if(timer){
            return false;
        }

        timer = setTimeout(function(){
            clearTimeout(timer);
            timer = null;
            self.apply(that, args);
        }, interval || 500);
    };
};

分时调用

/**
 * [timeChunk 分时调用]
 * @param  {[type]}   arr   [数据]
 * @param  {Function} fn    [处理函数]
 * @param  {[type]}   count [执行次数]
 */
var timeChunk = function(arr, fn, count){
    var obj, t, len = arr.length;

    var start = function(){
        for (var i = 0, obj; i < Math.min(count || 1, arr.length); i++){
            obj = arr.shift();
            fn(obj);
        }
    };

    return function(){
        t = setInterval(function(){
            if (arr.length === 0){
                return clearInterval(t);
            }
            start();
        }, 200);
    };
};

单例模式抽象

// 单例模式抽象
var getSingle = function(fn){
    var res;
    return function(){
        return res || (res = fn.apply(this, arguments)); 
    }
};